Unusual Destruction and Enhancement of Superfluidity of Atomic Fermi Gases by Population Imbalance in a One-Dimensional Optical Lattice
Qijin Chen1,2,3**, Jibiao Wang4**, Lin Sun2, Yi Yu5
1Shanghai Branch, National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Shanghai 201315 2Department of Physics and Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310027 3Synergetic Innovation Center of Quantum Information and Quantum Physics, Hefei 230026 4Laboratory of Quantum Engineering and Quantum Metrology, School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai 519082 5College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014
Abstract：We study the superfluid behavior of a population imbalanced ultracold atomic Fermi gases with a short range attractive interaction in a one-dimensional (1D) optical lattice, using a pairing fluctuation theory. We show that, besides widespread pseudogap phenomena and intermediate temperature superfluidity, the superfluid phase is readily destroyed except in a limited region of the parameter space. We find a new mechanism for pair hopping, assisted by the excessive majority fermions, in the presence of continuum-lattice mixing, which leads to an unusual constant Bose-Einstein condensate (BEC) asymptote for $T_{\rm c}$ that is independent of pairing strength. In result, on the BEC side of unitarity, superfluidity, when it exists, may be strongly enhanced by population imbalance.
. [J]. 中国物理快报, 2020, 37(5): 53702-053702.
Qijin Chen, Jibiao Wang, Lin Sun, Yi Yu. Unusual Destruction and Enhancement of Superfluidity of Atomic Fermi Gases by Population Imbalance in a One-Dimensional Optical Lattice. Chin. Phys. Lett., 2020, 37(5): 53702-053702.
An optical lattice in a theory paper in the literature often refers to a pure lattice in the context of a Hubbard model. Namely, a 1DOL means a simple 1D atomic chain. This is different from the 1DOL we study here.
Considering changing $t$ and $d$, here we define $k_{\rm F}$ and $T_{\rm F}$ as given by a homogeneous, unpolarized, noninteracting Fermi gas with the same total number density $n$ in 3D.
2020, Vol. 37 
